The exemplary embodiments described herein generally relate to devices and corresponding methods to increase the print quality of an inkjet printing system, including given a reduced printing speed.
Inkjet printing systems may be used for printing to recording media (paper, for example). For this, one or more nozzles may be used in order to spray, fire, or throw ink droplets onto the recording medium, and in order to thus generate a desired print image on the recording medium.
In operation, given inks that contain water components and solvent components, properties of the ink (the viscosity, for example) and/or properties of the droplet delivery from the nozzle (for example the droplet size, the droplet separation, the separation point in time, the flight behavior etc.) may change due to drying effects. A drying of the ink that begins within a nozzle therein for the most part produces a reduction of the achievable print quality, and may lead to a total failure of the nozzle.
EP2184168B1 describes an inkjet printing system in which a nozzle of the printing system is charged with a preparatory square wave pulse in order to prepare a printing system which reliably generates droplets with a small droplet size. DE69938385T2 describes an inkjet printer in which, after a longer printing pause, a prefire pulse may be generated before an ejection pulse. DE60121069T2 describes an inkjet printer that may switch between different resolutions in a primary scanning direction. DE60101297T2 describes an inkjet printer that may use different waveform elements for the ejection of ink.